IRIS Movie of the Day
At least once a week a movie of the Sun taken by NASA's Interface Region Imaging Spectrograph (IRIS) is posted by one of the scientists operating the instrument.
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6 Oct 2021
Colorized timelapse of AR12871
Credit: IRIS, LMSAL/NASA, Roy Smart
NOAA active region (AR) 12871 was scanned by the IRIS spectrograph 51 times over 6 days. The result is this 3-second timelapse, which shows the evolution of AR 12871, including the merging of two small sunspots. The color in this video was created by mapping the human visible light range to a +/- 50 km/s window around the Si IV 1394 Angstrom spectral line. This allows us to visualize subtle Doppler shifts of the spectral line, which are caused by glowing plasma in the solar atmosphere moving at high speeds. A pixel appears green if the plasma is stationary, blue if the plasma is flowing towards earth, red if the plasma is flowing away from earth, and purple if it is simultaneously flowing in both directions at once (an explosion).